1. Field of the Invention
The present invention relates to a method and apparatus for processing data, in which a power saving state is set in inoperative states of the respective components in a system equipment and these components are sequentially controlled to achieve power saving of the overall system.
2. Related Background Art
In a system equipment having a data processing unit as a main controller and a print controller to independently control the data processing unit and the print controller, when power saying of a printer unit of the system equipment is taken into consideration, transition states such as a stop state and a ready state are set and controlled by the main controller.
In the prior art described above, however, busy states occur at respective locations for the sake of operation convenience of the printer unit, and the main controller waits until these busy states are cleared. When data such as print data is to be transferred to the printer unit, it cannot be accepted unless the printer unit is ready, thus wasting time and power.
In the above prior art, however, in transfer of print data from the data processing unit, after the data processing unit and a power saving controller set the printer unit in a ready state, the printer unit receives data but is kept in the ready state until a print instruction is received, thereby wasting power.
In a conventional system having a data processing unit as a main controller and a print controller, power saving control of a printer unit is performed by a power saving controller in the data processing unit, and supply of power to the printer unit is performed in accordance with a supply instruction. The printer unit is powered off in response to a power-off instruction in accordance with status data representing an operating state or the like of the printer unit.
In this prior art system, the main controller must always monitor the status data, thereby wasting time and power.